lukefgee

Forgot to mention also had to clear out cache and cookies

Have found what I did wrong.
I installed over the top of v0.73 instead of deleting old files.

Here is what corrected it.

Updated WP from 2.3 to 2.5 as per
Extended upload instructions

Deleted Folder -> wp-content/plugins/nextgen-gallery/
Uploaded New version 0.92

Now works fine (including Visual editor)

I am having the same problem.
Running WP 2.5 with NextGen v 0.92

With the following browsers:
MAC : FF 2.0.0.13
Safari : 3.0.4 (5523.10)

Anyone found a work around for this?